Here's the development of the chosen thumb from my Alchemy explorations [link]
So this is the piece i did the walkthrough/tutorial with. The walkthrough will come later after i put em together and stuff. In this final image i changed his color to orange just so that he's not so similar to Bumble bee..lol!! ( Sory that the final design might not look as good as the thumb coz i got sidetracked doing the walktrough and stuff..urgh)
I like the color combo you used.
I didn't really try to colour alchemy stuff in PS yet... but this gives motivation.